1. Field of the Invention
This invention relates to complexes of zero-valent chromium containing six phosphite-ester ligands and to related hydride complexes.
2. Description of the Prior Art
Zerovalent metal complexes of metals such as nickel, iron, and molybdenum containing only phosphite-ester ligands are known. For example, in U.S. Pat. No. 3,997,579 Jesson and Tolman disclose the preparation of pentakis(trimethyl phosphite)iron and related compounds by evaporating metallic iron in a high vacuum and cocondensing the iron atoms with trimethyl phosphite.
Mathieu and Poilblanc, Inorg. Chem., 11, 1858 (1972), report the preparation of hexakis(trimethyl phosphite)molybdenum by displacing the carbonyl ligands of hexacarbonylmolybdenum with trimethyl phosphite in the presence of ultraviolet radiation. They were not able to make this reaction go to completion with hexacarbonylchromium or hexacarbonyltungsten. At the end of the article they state: "Apparently in the trimethyl phosphite series a combination of steric and electronic effects prevents hexasubstitution for Cr and W but permits it for Mo."
Libby and Bancroft, J. C. S. Dalton, 87 (1974), at page 89, Column 2, note the work of Mathieu and Poilblanc and state that their preparation of [Fe{P(OMe).sub.3 }.sub.6 ].sup.2+ and the existence of [Co{P(OMe).sub.3 }.sub.6 ].sup.3+ "suggest that there is probably no steric reason for not anticipating" the preparation of hexakis(trimethyl phosphite)chromium "by some other route."